This invention relates to a method of rendering oily and other difficultly adherable surfaces receptive to pressure-sensitive adhesives and to a primer having particular utility for that function.
In many fields of industry there are occasions when it is desired to apply a pressure-sensitive adhesive-coated sheet material to a greasy or oily surface. For example, filament tape is sometimes used to bind pipes together to facilitate handling; since such pipes are often coated with oil during manufacture or storage, it is difficult to obtain a firm bond with the tape. In other instances, it is desired to adhere anti-slip sheet material to the floor surfaces around a lathe or other piece of machine shop equipment, where the floor is frequently slippery because of the presence of oil. Lane marking tape is often adhered to factory floors to define areas and indicate passageways, and many factory floors are contaminated by the presence of oil.
In all instances where a normally tacky and pressure-sensitive adhesive tape is applied over an oily surface, the oil tends to prevent the adhesive from forming an intimate contact with the substrate. Even where extreme pressure is applied to promote such contact, the oil tends to plasticize the adhesive and render it more or less ineffective. It is, of course, essential that the adhesive establish and maintain intimate contact with the substrate, since a bundling tape which slips or a nonslip floor marking which comes loose may generate a misplaced confidence and hence be worse than none.
Recognizing the problem of obtaining adhesion to oily substrates, the prior art has resorted to such techniques as scrubbing the contaminated surface vigorously with a steel brush, washing with solvent, or both. Such techniques, while effective to a degree, are tedious, time-consuming and expensive. The present invention provides a unique, simple, and inexpensive alternative.